The present invention relates to an automatic lead supply apparatus for a plotter (or automatic drafting machine).
Lead has been supplied by moving a pencil holder held by the pen holder of a drawing head to a lead supply and discharge position and performing a knocking operation on the pencil holder, as disclosed in Japanese Patent Application Laid-Open No. 2-29399.
In the above-mentioned knocking operation, a plurality of leads housed in the knocking pipe of the pencil holder have often become caught in the vicinity of a chuck port 66a above a chuck portion, as shown in FIG. 4. Therefore, it has been impossible to supply the leads when this occurs. This phenomenon is especially prevalent when a main body of the plotter is inclined. Thus, it has generally been impossible to supply the lead when the plotter main body is inclined.